Broken tap extractor



Feb. 19, 1957 K. w. WEEKS BROKEN TAP EXTRACTOR Filed Jan. 27, 1955 INVENTOR. KENNETHW WEEKS. BY

fiTTORNEY.

BROKEN TAP EXTRACTOR Kenneth W. Weeks, West Hartford, Conn., assignor to The Walton Company, Hartford, Conn.

Application January 27, 1955, Serial No. 484,539

2 Claims. (Cl. 81--90) This invention relates to a broken tap extractor and more particularly to a tool for extracting broken taps firom threaded holes.

Heretofore, it has been common to provide an extractor having a plurality of fingers adapted to be projected from a shank to reach into the flutes of a broken tap so as to rotate is for extraction. In such common forms of extractors, the fingers have been held together by a common member slidable upon the shank and it has heretofore been necessary to project all of the fingers equally from the end of the shank.

Since it is sometimes found that one or more of the flutes of the broken tap are plugged up so that it is diflicult or impossible to insert some of the fingers into said plugged flutes for the same distance for which the other fingers may be inserted in their respective unplugged flutes, it is desirable to provide such an extractor in which each of the fingers may be inserted in their respective flutes of the tap for the full distance permissible by the condition of the flutes and independently of the other fingers.

It is therefore an object of this invention to provide such a broken tap extractor having novel means for adjustably securing each of the extractor fingers thereof to the shank independently of the other fingers.

A further object is the provision of such a broken tap extractor which is simple in construction, easy to use, economical to produce and highly eflicient in its operation.

Fuither objects and advantages of this invention will be more clearly understood from the following description and from the accompanying drawings in which:

Fig. 1 is a plan view of a broken tap extractor embodymg my invention.

Fig. 2 is a side view of said extractor.

Fig. 3 is an enlarged sectional view on line 3-3 of Fig. 2.

Fig. 4 is a bottom view.

As shown in the drawings, my improved broken tap extractor includes a shank 5 having a squared end 6, by means of which it may be turned, and a series of guide grooves 7, each of which contains an elongated finger 8 that is slida'ble in the groove and adapted to be pushed to extend from the end 9 of the said shank and thereby be inserted into a flute of a broken tap in a hole.

Each of said fingers is provided with a gripping portion 10 so that it may be readily pushed into the tap flute.

A sleeve 11 has an axial opening 12 through which the shank 5 is slidable with a substantially snug fit. The fingers are cross-sectionally of a lesser thickness than the depths of the grooves 7 so as to provide a loose fit permitting the said fingers to slide easily between the bottoms of their respective grooves and the wall of the opening 12.

It will be noted, from Fig. 3, that the outer crosssectional peripheries of the fingers are curved on a radius which is slightly smaller than the radius of the opening a; tates Patent 0 2,781,683 Patented Feb. 19, 1957 12 and has its center upon the axis of the said opening.

In order to adjustably secure the fingers within their respective grooves, so that they will project from the shank for the required distance independently of the other fingers, I provide a series of clamping screws 13 which extend radially through the Wall of the sleeve 11 and are threaded thereto. The said clamping screws are spaced around the said sleeve so that one of said screws will be in radial alignment with each of the fingers to thereby engage the outer surface of the finger and force it into clamping position against the bottom of its respective groove in the shank.

The said screws 13 are preferably located near the lower end of the sleeve 11 so that they may clamp the fingers to the shank near the lower end of the shank and thereby permit clamping of the fingers as near to the broken tap as possible.

In the use of my improved extractor, each of the screws 13 is loosened and the end of the shank 9 is then placed against the surface of the piece containing the broken tap. The fingers 8 are then independently pushed so that the lower end of each finger will be inserted into its respective flute of the broken tap as far as it will go. When all of the fingers have been thus inserted into the tap flutes, the sleeve 11 is moved into position against the surface of the workpiece and each of the screws 13 is tightened, so as to independently clamp the fingers to the shank, and the sleeve 11 will then retain the said fingers in their respective grooves during the rotation of the broken tap for its extraction.

I claim:

1. In a broken tap extractor, the combination of a shank having a plurality of elongated grooves in its outer surface, a series of fingers contained in said grooves and slidable therein to project ends of said fingers beyond a corresponding end of the shank, a sleeve slidable over said shank and fingers, and a plurality of clamping screws threaded to said sleeve and extending through the wall thereof into engagement with said fingers for clamping them against the bottoms of their respective grooves; said sleeve being snugly slidable upon the shank, and said fingers, when positioned in said grooves, having crosssectionally curved outer surfaces on the line of a circle of lesser diameter than the outer diameter of the shank to thereby provide a loose sliding fit for said fingers between the shank and the sleeve.

2. In a broken tap extractor, the combination of a shank having a plurality of elongated grooves in its outer surface, a series of fingers contained in said grooves and slidable therein to project ends of said fingers beyond a corresponding end of the shank, a sleeve slidable over said shank and fingers, and a plurality of clamping screws threaded to said sleeve and extending through the wall thereof into engagement with said fingers for clamping them against the bottoms of their respective grooves; said sleeve being snugly slidable upon the shank, and said finger, when positioned in said grooves, having crosssectionally curved outer surfaces on the line of a circle of lesser diameter than the bore of the sleeve to thereby provide a loose sliding fit for said fingers between the shank and the sleeve.

References Cited in the file of this patent UNITED STATES PATENTS 702,011 Kinvall June 10, 1902 1,218,522 Brown Mar. 6, 1917 2,539,532 Daniels Ian. 30, 1951 2,541,196 Brague Feb. 13, 1951 2,696,749 Cantin Dec. 14, 1954 

